Tetrasubstituted 1,3-Enynes by Gold-Catalyzed Direct C(sp2)-H Alkynylation of Acceptor-Substituted Enamines.

A gold-catalyzed synthesis of tetrasubstituted 1,3-enynes from hypervalent iodine(III) reagents and activated alkenes is reported. This reaction involves an in situ formed alkynyl Au(III) species and a subsequent direct C(sp2)-H functionalization of alkenes, offering 26 enynes in 62-92% yield with excellent functional group tolerance.